20516999 has 2 divisors, whose sum is σ = 20517000. Its totient is φ = 20516998.

The previous prime is 20516953. The next prime is 20517031. The reversal of 20516999 is 99961502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20516999 - 2¹⁶ = 20451463 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20516939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10258499 + 10258500.

It is an arithmetic number, because the mean of its divisors is an integer number (10258500).

Almost surely, 2^20516999 is an apocalyptic number.

20516999 is a deficient number, since it is larger than the sum of its proper divisors (1).

20516999 is an equidigital number, since it uses as much as digits as its factorization.

20516999 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 43740, while the sum is 41.

The square root of 20516999 is about 4529.5694055837. The cubic root of 20516999 is about 273.7608112047.

The spelling of 20516999 in words is "twenty million, five hundred sixteen thousand, nine hundred ninety-nine".